1. Field of the Invention
The present invention relates to a mobile communication terminal having a plurality of modems. More particularly, the present invention relates to a connection structure of the plurality of modems and a Subscriber Identity Module (SIM) card and a method and apparatus for performing an operation by using the connection structure.
2. Description of the Related Art
With the development of electrical and electronic technologies and a variety of communication techniques, mobile communication terminals supporting a plurality of communication systems by including a plurality of modems have recently been launched, and research for more effective operations of these mobile communication terminals is in progress. For example, there is ongoing research for providing control by effectively connecting a plurality of modems and a Subscriber Identity Module (SIM) card in the mobile communication terminals.
In general, the connection and operation between the modems and the SIM card require four interfaces (e.g., a Voltage (VCC) line for supplying power, an Input-Output (IO) line for transmitting/receiving a polling signal and data, a Clock (CLK) line for providing a clock, and a Reset (RST) line for resetting the SIM card). A mechanism for connecting the plurality of modems and the SIM card is under research to obtain high efficiency in terms of systems.
FIG. 1 and FIG. 2 illustrate a connection structure of a SIM card and a plurality of modems in a mobile communication terminal according to the related art.
Referring to FIG. 1, each of a modem A 100 and a modem B 110 may be connected to a SIM card 120 through four interfaces, or as illustrated in FIG. 2, only a modem A 200 may be connected to a SIM card 220 through four interfaces and a modem B 210 may communicate with the SIM card 220 via the modem A 200. However, the structure of FIG. 1 has a problem in that, when a mode transition occurs from a mode of using the modem A 100 to a mode of using the modem B 110, SIM related information obtained during the operation of the modem A 100 may be lost. Meanwhile, the mechanism of FIG. 2 may prevent the SIM card 220 from being reset when an operation of the modem A 200 is switched to an operation of the modem B 210, and also has a problem in that the modem A 200 has to be periodically awakened for a polling operation during the operation of the modem B 210, thereby causing additional current consumption.